wtcc5's TT-02 race development and race reports: Race report from the RCKleinSerie @ the IRS

[wtcc5 5804]

Thank you 

I decided to accompany the build with a video series.

The first one is not so thrilling, but helps my customers to prepare the parts for the build. Also the custom parts are shown better than before:

 

[wtcc5 5804]

The last two days I build the car. It was a very nice experience. Shapeways did a brilliant job regarding the dimensions of the parts. The same counts for Ahltec who made the cf parts. Except for the top plate "spacer" (my fault, I need to make them lower by 3 tenth) there was nearly no fitting necessary. The preparations took a lot of time and the hasslefree build then was very enjoyable. I filmed the whole build, that is why I made no extra pictures of it. Recording a build is no fun. I will post the video link here in the coming days.

But I won't let you wait for the result 

 

Edit:

I forgot one thing:

It is now 41g lighter than the v2 

[wtcc5 5804]

The time lapse build video is online:

 

[ryback 61]

Wow - work of art. Half tempted to build one myself just because it looks so good, even though I know it'd be essentially pointless (I don't race)!

[wtcc5 5804]

Today I installed the electronics. It was a kind of „plug and play“ as I didn’t change the layout:






On the scale:

[wtcc5 5804]

A lot of new GT bodies were released since I regularly raced the RCKleinserie. For this new version I was keen to get the ZooRacing BWOAH! This Aston Martin Valkyrie body has nice lines and looks sophisticated. I hope chassis and body will work in harmony 










 

[wtcc5 5804]

… and another video of the car with me babbling about its specs 

 

[wtcc5 5804]

The car already had its maiden run and pretty much felt and behaved similar to the KRv2. All parts did their job and held well. A real practice day at the racetrack is still needed to verify its performance and to find a strong base setup.

One thing I haven’t done good was the setup previous to the maiden run (as this got a little more complicated with the new suspension). To work with the caster angles, I drew and printed caster-angle-indicators. 
 

 

 

I use the rear hub screw to attach the indicator. With its shape it sits flush with the steering arm part.

[Pylon80 4003]

On 6/29/2021 at 8:59 AM, wtcc5 said:

Today I installed the electronics. It was a kind of „plug and play“ as I didn’t change the layout:






On the scale:

I am surprised you could balance it with a shorty pack on the left and everything else on the right. Amazing custom work!

[wtcc5 5804]

As my hub design is nice, but a little on the weak side regarding hard impacts, I spoke to a friend who knows how to design aluminium and has people who know their job very well regarding manufacturing aluminium parts. After simplifying the design he made sure the right tolerances were used to make the bearings sit just perfect.

The parts arrived some days ago and I couldn’t wait to add them to the car:









I installed them front and rear. With that the car should be „bulletproof“ 

[wtcc5 5804]

Unfortunately, the cardans are a tiny bit too short to work with my hubdesign, which leads to the bone leaving the outdrive. Reality is brutal  I learned that a week ago on an indoor circuit. So at the front I use „plan B“ TRF420 steering hubs now.
 

Today I was outdoor at the AMSC Augsburg:

I finally (and a little surprisingly) had a 0.75 practice day. Unfortunately rain shut down the day with me having the car in the hand to put it on track…

My mood was way too good to be angry about the rain. Goal for this day was to find a harmonic setup, a trusty rear end and a car that can be pushed, but stays calm. Sounds a little weird… I like to drive a little bit over the limit and need a car that rotates with ease and has a sharp turn in. All that did I find today.



In the first two runs, the car was a handful to drive. After checking the setup, I was disappointed by myself. Especially the rear was more wrongs than rights. Droop, shock length, camber, ride height… all total chaos or not there. I adjusted everything and made the front, too.



Now, the setup work could begin. The rear loved to make a side step everytime I accelerated out of a corner. The KRv2 had this behavior too, so it was time to get rid of it. Softer rear springs (2.3) didn’t solve the problem, but suited the track better. As I felt a lack of grip, I removed the rear anti-roll-bar. Again the rear got better. Removing the front arb also made a huge difference. The car became more alive and made the tires work better. Maybe the car is so low and wide now, that it doesn’t need stabilizers for medium grip asphalt anymore.
The laptimes came down from 17.2s to 16.9s.
For years I have used Volante Hybrids. With their carpet insert, they generated more grip and were faster. But they also made the car nervous in its behavior. On my last race, couldn’t stand that anymore and used „normal“ Volante, because the car became much easier to drive. The fastest lap was slower, but overall faster and more comfortable. Today I gave the hybrids a last chance… and it is over for them now. I used the Volante 36 from then on and heated them to 58*C for 12 minutes.
I made more changes to the front: Ackermann, toe, springs, droop, bump steer. And somehow I was on a stroke of luck. Most of my ideas worked, made the car easier to drive and faster. I could manage 16.8s easier and more often and had less times drop throughout the run.
In the end my best laptimes were 16.6s. And I used another tire set of a different manufacturer, that worked even better regarding grip and behavior when driving on the limit. So overall a very productive day.

I also got to know the car better 



I had some loose screws and brought homework home. I can’t exactly tell when I will race the next time, but now I am looking forward to it 

 

[wtcc5 5804]

Caster pointers for the TRF420 hubs...





Updated setupsheet for the KRv4 chassis to save yesterdays setup:



And ... I ordered MTC2 springs. These are softer than the Xray versions (down to 1.89) and maybe unlock even more performance 

[wtcc5 5804]

The first race for the KRv4 is coming up. It will be at the EMC Marktoberdorf, a track that I visited two times with the KRv2 already. From one of the past races I know my laptimes. A thing that was very important for me today, as I took the opportunity to practice there today.





I started practice on medium old tires and had to relearn the rhythm again. Once it came back, I focussed on the line in the difficult areas. With that, good laptimes came. My personal best from 2019 (see race report here earlier) was 20.090s. Through the day, I managed 20.028s as personal best with the tires dying (cuts and belt visible) and a lot of 20.0s and 20.1s laps. Not by much, but the KRv4 was always faster, than the KRv2.

Tire preparation was a little strange. 58*C seems to be just perfect. At some time the use of additive made the grip worse at the start of the stint. So I just heated the tires and it was fine again.

For the last run, I used a new set of tires and wanted to know how effective the tire preparation with additive would be. And it worked fine, so with aging tires I need to stop using tire additive to prevent a performance loss in the first laps of a run.

The last run with new tires then was awesome. The car felt nailed to the track and was super save to maneuver through the fast sections. In the end a lot of 19.6s laps appeared on the timing screen. Four tenths faster than my previous best with the KRv2. Very satisfying! Setup wise, I changed to softer Mugen springs, softer oil and increased caster and camber. I tried anti-roll-bars (1.1 and 1.2), but these did nothing good, like everything else I tried.
Now I hope, I have set the bar high enough for a good race weekend 

[wtcc5 5804]

Michael, my good friend, first-hour-TT02KR-owner and „business angel“ regarding the TT02 conversions was competing at the ETS last weekend. In the breaks between the runs, he showed around the KRv4.

If I remember correctly, he „rubbed in the faces“ of Martin Hudy (Xray Designer) and Ronald Völker (Mugen Team Driver) 

As he was driving to Andernach together with Max Mächler (Awesomatix Team Driver), Max got the time to take a closer look at it, too.

But he wasn’t satisfied there and gave it to a Mikanews (a german R/C news site) reporter. This guy then made a nice article:

https://mikanews.de/2021/08/19/tt-02-krv4-von-kevin-kreft-entwickelt-fuer-die-gt-sport-klasse/

[wtcc5 5804]

The first race for the v4 is already in the books!

It was one of the most dominant races of my R/C „career“. The car was easy to drive. The fast corners were my territory. In these areas I made up so much ground. I also could accelerate sooner and harder into the full throttle zones.
I took TQ easily and in the finals my laptimes were partially up to one second faster than the next competitor. Only in one qualifier I rolled the car, which costed about three seconds. On every other heat I stayed clean. I could also repeat my 19.6s fastest lap, even though the track was much hotter than on wednesday practice.

Some pictures of my „place“:



With „track view“:



Because of my late registration all pit spaces were already occupied, but the club was very nice and had huge parasol for me.

In between qualifying, the weather forecast predicted heavy rain on sunday, so the race director changed its plan and reduced the qualifying heats from five to two and did all three finals today (not sunday). That meant, that the last finals nearly happened in the dark.
The award ceremony did. That is my first night picture with cup 

 

First race, first win… couldn’t be much better. The car was bulletproof and the only „failure“ was one screw that was a tiny bit loose.

[ThunderDragonCy 8607]

Congratulations! Fantastic job

 

[wtcc5 5804]

https://fb.watch/7NJ9KZiSFA/

A friend filmed one of the heats of last race. You can’t see my car very often, but it's something 

[ruebiracer 1213]

Awesome work again Kevin, following your mods on rc tech for some years now! Very cool, that you could even improve your V2 with the V4! I espacially like the new shock towers integrated in the bulkheads, adjusting the shock angle with spacers!  But also the new hub design looks very cool.

All the best for the next races and your customers! I could even see one of your conversions 2 years ago running an RCK race in "Hassfurt am Main", where I competed in the Porsche cup the first time with my TA02.

And some very sad news beside: Tamiya shut down the famous "Euro Race way" in Sonneberg some weeks ago. So our classics Tamiya buggy run will never be possible there again... Stupid managers, who are not involved in the hobby themselves. They just decided to use the space for making the logistics centre bigger...

Only positive news is, tht the local club could save the nice tribune/Drivers stand/pit area and is taking them to their new site some kilometres away. So this very nice wood building has a second life...

Kind regards,

Matthias

[wtcc5 5804]

Yeah, sad news indeed. Also the way it leaked shows, that Tamiya doesn’t care very much anymore. 

[wtcc5 5804]

In Germany the weather is cold again. I decided to join the Indoor Racing Senden club and already had two practice days with the KRv4.



The car was great from the start. I did some setup work and also changed the aluminum hubs back to the 3d-print-type. They survived both days so far (yes, I hit the boards several times). The car still doesn't like the anti-roll-bar in front. Other changes had the intention to make it rotate better. Less toe-in and the anti-roll-bar in the rear worked very good. I also tried different caster angles in front and found 5° to work best. Unfortunately I am not sure how much the times I drove with the KRv2 are worth, as the track layout was changed last year and I only have had recorded one practice run of the last time the v2 drove there.


At that time I had a fastest lap of 10.331s and 29L in 5:08.948min. Last sunday with the KRv4 I could lower that time to 10.107s and 29L in 5:01.561min.



With track evolution, more practice and maybe some more setup tweaks I hope to break through the 10s-barrier.


In between and with the experience of the last race and practice runs, I worked on a life-cycle-impulse for the v4. Some things are bothering me, especially the time consuming setup work (it is not that bad, but I am lazy ) and also the location of the shocks, because of the camberlink upper arms.



I just wanted to change a few parts initially, but it became nearly a complete overhaul...
The first thing visible are the carbon upper arms together with Awesomatix quick release mounts. There will be several proven geometries available (caster and camber). Like this I can change the front setup in some seconds and without a screwdriver or setup system. These "fixed-geometry" arms allow to move the damper 10mm closer to the centerline of the lower arm (reducing tweak) and are lighter.




Same philosophy for the rear. With the new rear shock position, it made sense to combine body posts and shock mounts. The wheelbase was reduced by one millimeter:




The hubs got a new design, too. I beefed them up a little and made an interlock form to prevent the attached carbon plates from unwanted twisting. The rear hubs now sport a very low active-toe-system.

Except for the battery mount every part was optimized/changed to suit the design (like Xray: "All new!" everytime ). 

 

[blu-tak 3]

Well this is truly amazing engineering and custom work.

 

I'd love to see you build a 'rally' tt02. This would make you look the chassis in a different way potentially.

[wtcc5 5804]

@blu-tak: I am not so sure about that. You want long arms for Off-road and long shocks. So the same design with higher shocktowers would probably be sufficient… What else is special on Rallye cars (except for the ride height)?

 

The parts for the KRV4 lci are nearly complete. I am just waiting for a delivery by Monaco RC (Officina RC titanium ballstuds). Today the carbon parts arrived:

 

[wtcc5 5804]

My TT02 development is in the german rc magazine:

https://www.cars-and-details.de

[wtcc5 5804]

Lets add the new parts (nearly a complete rebuild )! 


The upgrade parts:




The cleaned 3D-print parts:




Work table mess:




Front lower arms, bumper and droop plate:








Attached to the tub chassis:




Top plates added:




Front hubs and upper arms: I use Officina Titanium ballstuds to keep the weight down and have the perfect fit for the ballcups.








The Awesomatix ball cups received a 3mm hole to make working on the car easier:




Finished front:






 

[wtcc5 5804]

Same procedure for the rear.


Droop plate and arms:




Active toe posts and links added:






Mount for damper and anti-roll-bar:




Droop plate and top plate attached to the tub chassis:




Rear hubs, upper arms and ballcups:









The assembled car:












Unfortunately the rear dimensions/suspension angles are off  Right now I am reviewing where the fault is. I am suspecting the droop plate as it not only misses a countersunk hole, but doesn't seem to sit centered on the chassis...